Preparation method of ternary transition metal sulfide electrode material and application thereof in electrocatalytic sulfur oxidation (SOR) coupling hydrogen production reaction

Abstract

This invention discloses a ternary transition metal sulfide (CuCoNiS) x The preparation method of electrode materials and their performance in electrocatalytic sulfur oxidation (SOR) coupled hydrogen production. Ternary transition metal hydroxides were prepared by electrodeposition using copper nitrate (Cu(NO3)2), nickel nitrate (Ni(NO3)2), and cobalt nitrate (Co(NO3)2) as copper, nickel, and cobalt sources, respectively. Based on this, CuCoNiS was prepared by hydrothermal in-situ sulfidation using sodium sulfide as the sulfur source. x Compared to single-site copper sulfide (CuS), the introduction of Co and Ni effectively modulates the electronic structure of the catalyst, enhancing its conductivity and structural stability, and significantly improving its catalytic activity and resistance to sulfur poisoning in the electrocatalytic sulfur oxidation reaction (SOR). The catalyst prepared in this invention exhibits excellent electrocatalytic performance and long-term stability, and the synthesis process is relatively simple. It is suitable for energy conversion fields such as hydrogen sulfide decomposition to produce hydrogen, showing good prospects for industrial application.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalysis technology, and specifically discloses a method for preparing and applying a ternary transition metal sulfide bifunctional electrocatalyst. Background Technology

[0002] Hydrogen energy is a clean and low-carbon energy source, and water electrolysis is an important way to achieve its large-scale production. Traditional water electrolysis systems use the oxygen evolution reaction (OER, 1.23 V vs. RHE) as the anode reaction, which has disadvantages such as slow kinetics, high overpotential, and high energy consumption (Suen NT et al., Chem. Soc. Rev., 2017, 46, 337-365), which seriously limit the efficiency of hydrogen production. In contrast, using sulfide ion oxidation reaction (SOR, E = -0.48 V vs. SHE) instead of OER to construct a sulfur oxidation coupled hydrogen production system can significantly reduce the energy barrier of the anode reaction and achieve low-energy hydrogen production (Yu Z. et al., Adv. Funct. Mater., 2024, 34, 2403435), while simultaneously completing the resource-based treatment of sulfur-containing pollutants (Zhang S. et al., Adv. Funct. Mater., 2021, 31, 2101922). It has important application value and prospects in the fields of industrial waste sulfur treatment and green hydrogen production.

[0003] Among existing technologies, transition metal sulfides (TMSs) have become one of the most widely used catalytic materials in the field of solubility in oxidative stress (SOR) due to their unique physicochemical properties (Yu Z. et al., Adv. Funct. Mater., 2024, 34, 2403435). Compared with oxygen, sulfur has lower electronegativity and a larger atomic radius, making the metal-sulfur bonds in TMSs more easily polarized and the electron cloud more easily shifted towards the metal site (Jaramillo TF et al., Science, 2007, 317, 100-102), thereby enhancing the adsorption and activation ability of active sites for sulfur ions. At the same time, intrinsic defects such as sulfur vacancies and edge unsaturated coordination on their surface can further modulate the electronic structure, improving the intrinsic catalytic activity and stability (Xie J. et al., Adv. Mater., 2013, 25, 5807-5813). Meanwhile, transition metal sulfides typically exhibit good conductivity and high affinity for sulfur-containing electrolytes, making them promising candidates for SOR reactions. However, the widely studied monometallic / bimetallic sulfides still face several bottlenecks: on the one hand, their limited number of intrinsic active sites and insufficient tunability of electronic structure make it difficult to match the kinetics of sulfur adsorption and conversion with the hydrogen evolution reaction (HER) (Zhou W. et al., J. Colloid Interface Sci., 2024, 655, 75-90), hindering efficient synergistic bifunctional catalysis; on the other hand, these materials generally exhibit poor conductivity and long-term stability (Faber MSet al., J. Am. Chem. Soc., 2014, 136, 10053-10061).

[0004] To overcome the aforementioned technical bottlenecks, this invention designs ternary transition metal sulfides and precisely regulates the electronic structure of these ternary transition metal sulfides, optimizing the binding strength between active sites and reaction intermediates to achieve a moderate adsorption process. This significantly enhances the catalytic activity, durability, and resistance to sulfur poisoning of the catalyst. Based on this, a bifunctional ternary transition metal sulfide electrocatalytic material with structural stability, high conductivity, and excellent resistance to sulfur poisoning is developed and applied to a sulfur oxidation coupled hydrogen production system. This has significant scientific and engineering value for promoting efficient, low-energy hydrogen production and the resource utilization of sulfur-containing pollutants. Summary of the Invention

[0005] This invention provides a ternary transition metal sulfide (CuCoNiS) xThe method for preparing the catalyst utilizes electrocatalytic coupling to achieve efficient hydrogen production and sulfur oxidation reactions. The catalyst prepared by this method possesses high SOR-HER bifunctional activity, excellent structural stability, and resistance to sulfur poisoning. It can achieve synergistic effects of low-energy hydrogen production and resource utilization of sulfur-containing pollutants, and can be applied to industrial and large-scale production.

[0006] Specific This invention provides a method for preparing ternary transition metal sulfides, characterized by its ability to effectively remove and recycle toxic sulfide waste and produce hydrogen efficiently and at low cost. The method is as follows: An electrolytic cell containing a cation exchange membrane was used, with a ternary transition metal sulfide material supported on a nickel foam substrate as both the cathode and anode. Sodium hydroxide (NaOH) solution was added to the cathode reaction chamber as the cathode electrolyte, and sodium hydroxide and sodium sulfide solutions were added to the anode reaction chamber as the anode electrolyte. The electrolytes in the anode and cathode reaction chambers underwent a coupled electrolytic reaction at room temperature and with stirring. Finally, sulfur was obtained as the product in the anode reaction chamber, and hydrogen was obtained as the product in the cathode reaction chamber. The bifunctional catalyst was prepared by the following method: (1) Cleaning the nickel foam substrate (2) Preparation of copper nitrate (Cu(NO3)2), nickel nitrate (Ni(NO3)2), and cobalt nitrate (Co(NO3)2) 3)2 The electrolyte was prepared by using the cleaned nickel foam, Ag / AgCl and platinum mesh from step (1) as the working electrode, reference electrode and counter electrode, respectively, and treating them at the reduction potential for a period of time. After the reaction was completed, the resulting materials were washed and dried.

[0007] (3) Prepare an electrolyte containing sodium sulfide nonahydrate, add the nickel foam obtained in step (2), and keep it in the reactor for a certain period of time; wash and dry the resulting material.

[0008] Furthermore, the amount of Cu(NO3)2, Ni(NO3)2, and Co(NO3)2 added was 0.4 mmol each, dissolved in 50 mL of deionized water.

[0009] Furthermore, the solution is stirred for 25–30 minutes. Furthermore, the reduction potential was -1.0 V vs. Ag / AgCl, and the reaction time was 15 min.

[0010] Furthermore, the material is washed with deionized water and dried at room temperature.

[0011] Furthermore, 0.18 g of Na2S·9H2O was added and dissolved in 40 mL of deionized water.

[0012] Furthermore, the reaction temperature in the reactor is 110–130 °C, and the reaction time is 8 h.

[0013] Furthermore, the material is washed three times each with deionized water and anhydrous ethanol, and then vacuum dried at 50–70°C.

[0014] This invention proposes a method for preparing ternary transition metal sulfides, which can be used for efficient sulfide removal and hydrogen production. The first inventive point is that by precisely controlling the molar ratio of copper, nickel, and cobalt, the electronic structure of the ternary transition metal sulfide is precisely controlled, optimizing the binding strength between active sites and reaction intermediates, thus moderateing the adsorption process and significantly improving the catalytic activity, durability, and resistance to sulfur poisoning of the catalyst, simultaneously achieving efficient SOR and HER reactions. The second inventive point is the use of sodium sulfide for sulfidation, which promotes the reaction and improves the reaction efficiency. This method can achieve efficient, low-energy coupled hydrogen production at room temperature and pressure. The reaction process conditions are mild, the raw materials are low-cost, and the operation is highly operable, making it suitable for large-scale preparation and showing good prospects for industrial application. Attached Figure Description

[0015] Figure 1 CuCoNiS x and CuCoNi(OH) x X-ray diffraction (XRD) energy spectrum Figure 2 Field emission scanning electron microscopy (FESEM) images of different catalysts: (a) CuCoNi(OH) x / NF;(b)CuCoNiS x / NF Figure 3 Electrocatalytic sulfur oxidation performance of different electrode materials: (a) LSV curves (1 M NaOH + 1 M Na2S); (b) Potential comparison of different materials at industrial-grade current densities; (c) CuCoNiS x Comparison of SOR and OER linear sweep voltammetry (LSV) curves for / NF; (d) Tafel slopes for different materials; (e) Nyquist plots for different materials (-0.5 V vs. RHE, 10 -2 -10 5 Hz) Figure 4 Electrochemical active area determination diagram of different electrode materials: (a) CuCoNiS x / NF,(b)CuCoNi(OH) x / NF, (c) NF, (d) Sulfur oxidation active area of ​​each catalyst normalized by ECAS; Figure 5 S of electrode material2- Adsorption performance and electrocatalytic stability: (a) S of different materials 2- Adsorption capacity comparison; (b) CuCoNiS x / NF and CuS x / NF chronopotential curve; (c) CuS x / NF chronocurrent curve; (d) CuCoNiS x Cyclic stability of / NF Figure 6 In-situ Raman spectra of different catalysts under SOR conditions (-0.45 V vs. RHE): (a) CuCoNiS x / NF;(b) CuS x / NF Figure 7 Electrocatalytic hydrogen evolution (HER) performance of different electrode materials: (a) LSV curves of different materials (1 M NaOH); (b) Overpotentials of different materials at different current densities; (c) Tafel slopes of different materials; (d) Nyquist spectra of different materials (0.1 V vs. RHE, 10 -2 -10 5 Hz) Figure 8 CuCoNiS x Comparison of hydrogen production performance of / NF in SOR / / HER and OER / / HER systems: (a) LSV curves; (b) Comparison of cell voltage at different current densities. Example

[0016] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, embodiments and comparative examples are provided to illustrate the present invention in more detail, but the present invention is not limited to these embodiments without departing from its spirit.

[0017] CuCoNiS x / NF Nickel foam was ultrasonically treated with acetone for 15 min to remove surface oil. Further, it was ultrasonically treated with ethanol for 15 min to remove residual acetone. Further, it was ultrasonically treated with 3 M hydrochloric acid for 15 min to remove metal oxides from the surface. Further, it was ultrasonically treated with ethanol multiple times until the solution was clear and colorless. Further, it was vacuum dried for 40 min. Further, 0.4 mmol of each of Cu(NO3)2, Ni(NO3)2, and Co(NO3)2 were placed in a beaker containing 50 mL of deionized water and stirred for 30 min until completely dissolved. Further, NF, Ag / AgCl, and Pt mesh were used as the working electrode, reference electrode, and counter electrode, respectively, and treated at -1.0 V vs. Ag / AgCl for 15 min. Further, the obtained material was washed with deionized water and dried at room temperature. Further, 0.18 g of sodium sulfide nonahydrate was placed in a beaker containing 40 mL of deionized water and stirred for 30 min. A mixed solution was formed after min; further, the above solution was transferred to a Teflon stainless steel autoclave and heated at 120 °C for 8 h; further, the obtained material was washed three times with deionized water and anhydrous ethanol, respectively, and then placed in a vacuum oven and dried at 60 °C to obtain CuCoNiS x / NF.

[0018] Comparative Example 1 CuCoNi(OH) x / NF Nickel foam was ultrasonically treated with acetone for 15 min to remove surface oil. Further, it was ultrasonically treated with ethanol for 15 min to remove residual acetone. Further, it was ultrasonically treated with 3 M hydrochloric acid for 15 min to remove metal oxides from the surface. Further, it was ultrasonically treated with ethanol multiple times until the solution was clear and colorless. Further, it was vacuum dried for 40 min. Further, 0.4 mmol of each of Cu(NO3)2, Ni(NO3)2, and Co(NO3)2 were placed in a beaker containing 50 mL of deionized water and stirred for 30 min until completely dissolved. Further, NF, Ag / AgCl, and Pt mesh were used as the working electrode, reference electrode, and counter electrode, respectively, and treated at -1.0 V vs. Ag / AgCl for 15 min. Further, the obtained material was washed with deionized water and dried at room temperature to obtain CuCoNi(OH). x / NF.

[0019] Comparative Example 2 CuS x / NF Nickel foam was ultrasonically treated with acetone for 15 min to remove surface oil. Further, it was ultrasonically treated with ethanol for 15 min to remove residual acetone. Further, it was ultrasonically treated with 3 M hydrochloric acid for 15 min to remove metal oxides from the surface. Further, it was ultrasonically treated with ethanol multiple times until the solution was clear and colorless. Further, it was vacuum dried for 40 min. Further, 0.4 mmol of Cu(NO3)2 was placed in a beaker containing 50 mL of deionized water and stirred for 30 min until completely dissolved. Further, NF, Ag / AgCl, and Pt mesh were used as the working electrode, reference electrode, and counter electrode, respectively, and treated at -1.0 V vs. Ag / AgCl for 15 min. Further, the obtained material was washed with deionized water and dried at room temperature. Further, 0.18 g of sodium sulfide nonahydrate was placed in a beaker containing 40 mL of deionized water and stirred for 30 min to form a mixed solution. Further, the above solution was transferred to a Teflon stainless steel autoclave and heated at 120 °C for 8 minutes. h; Further, the obtained material was washed three times with deionized water and anhydrous ethanol, respectively, and then dried in a vacuum oven at 60 °C to obtain CuS. x / NF.

[0020] Comparative Example 3 CoNiS x / NF Nickel foam was ultrasonically treated with acetone for 15 min to remove surface oil. Further, it was ultrasonically treated with ethanol for 15 min to remove residual acetone. Further, it was ultrasonically treated with 3 M hydrochloric acid for 15 min to remove metal oxides from the surface. Further, it was ultrasonically treated with ethanol multiple times until the solution was clear and colorless. Further, it was vacuum dried for 40 min. Further, 0.4 mmol each of Ni(NO3)2 and Co(NO3)2 were placed in a beaker containing 50 mL of deionized water and stirred for 30 min until completely dissolved. Further, NF, Ag / AgCl, and Pt mesh were used as the working electrode, reference electrode, and counter electrode, respectively, and treated at -1.0 V vs. Ag / AgCl for 15 min. Further, the obtained material was washed with deionized water and dried at room temperature. Further, 0.18 g of sodium sulfide nonahydrate was placed in a beaker containing 40 mL of deionized water and stirred for 30 min. After min, a mixed solution is formed; further, the above solution is transferred to a Teflon stainless steel autoclave and heated at 120℃ for 8 h; further, the obtained material is washed three times with deionized water and anhydrous ethanol respectively, placed in a vacuum oven, and dried at 60 ℃ to obtain CoNiS. x / NF.

[0021] Experiments and Data 1. Catalyst performance testing A three-electrode H-type electrolytic cell was constructed, with the two chambers separated by an anion exchange membrane, using CuCoNiS... x The / NF electrode was used as the working electrode, the platinum mesh electrode as the counter electrode, and the Hg|HgO electrode as the reference electrode. The electrolyte used in the test was 1 M NaOH, and the instrument used was a Chenhua 660E electrochemical workstation. Specific test conditions were as follows: Test method: LSV-Linear Sweep Voltammetry Scan speed: 0.005 V / s Voltage stabilization time: 2 seconds Sensitivity: 1.e -001 A / V Each chamber was filled with 10 mL of 1M NaOH. During testing, the portion of the catalyst immersed in the liquid was 1 x 1 cm to minimize the impact of resistance on the actual performance of the catalyst. After testing the oxygen evolution performance of water electrolysis, 1 M sodium sulfide was added to the anode, and the same method was used to test the sulfide oxidation (SOR) performance of the catalyst.

[0022] 2. SOR Product Testing A three-electrode H-type electrolytic cell was constructed, with the two chambers separated by a cation exchange membrane, using CuCoNiS... x / NF was used as the working electrode, platinum mesh electrode as the counter electrode, and Hg|HgO as the reference electrode. The electrolyte used in the test was 1 M NaOH + 1 M Na2S, and the instrument used was a Chenhua 660E electrochemical workstation. The specific test conditions are as follows: Test method: it Curve Runtime: 8 hours Voltage stabilization time: 2 seconds Sensitivity: 1.e -001 A / V Each chamber was filled with 10 mL of 1 M NaOH, and 2.4 g of Na₂S·9H₂O was added to the anode to achieve a concentration of 1 M. During testing, the catalyst was immersed in the liquid to a depth of 1 x 1 cm. 20 μL of electrolyte samples were collected at different time points (0, 0.5, 1, 2, 4, 6, 8 h) and immediately diluted (100-fold). Spectroscopic measurements were performed using a UV-Vis spectrophotometer at 250–450 nm.

[0023] 3. SOR stability test A three-electrode H-type electrolytic cell was constructed, with the two chambers separated by a cation exchange membrane, using CuCoNiS... xThe / NF electrode was used as the working electrode, the platinum mesh electrode as the counter electrode, and the Hg|HgO electrode as the reference electrode. The electrolyte used in the test was 1 M NaOH, and the instrument used was a Chenhua 660E electrochemical workstation. Specific test conditions were as follows: Test method: it Curve Test potential: 0.4 V vs. RHE Runtime: 12 hours Voltage stabilization time: 2 seconds Sensitivity: 1.e -001 A / V The cathode electrolyte is 60 mL of 1 M NaOH, and the anode electrolyte is 60 mL of 1 M NaOH + 1 M Na2S. The anode electrolyte is replaced every 12 h.

[0024] Experimental results 1. CuCoNiS x Successful preparation of / NF materials The catalyst prepared by the method described in this embodiment was characterized by X-ray diffraction (XRD). Figure 1 The image shows the XRD pattern of the material, CuCoNi(OH). x The XRD pattern showed peaks at 12°, 24.0°, 34.3°, and 60.1°, indicating that the precursor contained a typical hydrotalcite-like structure (JCPDS No. 89460). After hydrothermal sulfidation, the characteristic diffraction peaks of the precursor LDH disappeared, confirming the precursor's transformation into a sulfide. CuCoNiS x The XRD pattern is consistent with the standard Cu(Co, Ni)S4PDF card, with distinct peaks at 32°, 38°, 50° and 55°.

[0025] CuCoNiS was observed using field emission scanning electron microscopy (FESEM). x Surface morphology of / NF. For example... Figure 2 a, CuCoNi(OH) x The / NF precursor exhibits a uniform nanosheet array structure, vertically grown on the surface of the NF framework. For example... Figure 2 b. After sulfurization treatment, the surface morphology of the material undergoes significant changes. The original nanosheet structure transforms into a rough surface structure composed of nanoparticles, with a large number of nanoparticles uniformly distributed on the substrate surface. This unique structure can significantly increase the specific surface area and reaction site exposure of the material, thereby effectively enhancing its electrocatalytic activity.

[0026] 2. CuCoNiS x / NF electrocatalytic performance like Figure 3As shown in (a, b), CuCoNiS x Only a low potential of 0.22 V vs. RHE is required to reach 100 mA·cm. -2 Current density; such as Figure 3 c, Compared to OER, CuCoNiS x Achieving an industrial-grade current density of 100 mA·cm -2 and 200 mA·cm -2 The potential decreased significantly by 1.18 and 1.30 V, indicating that the system can significantly reduce hydrogen production energy consumption by approximately 50%. For example... Figure 3 d, CuCoNiS x The Tafel slope is 22.47 mV·dec -1 Far lower than NiS x CoS x and CoNiS x (38.85, 26.58 and 28.85 mV·dec) -1 ), only higher than CuS x (12.84 mV·dec) -1 SOR reaction kinetics has significant advantages; in addition, CuS x The charge transfer resistance is lower than that of CuCoNiS x ( Figure 3 e), which is superior to CuCoNiS in terms of electrocatalytic performance and reaction kinetic rate. x .

[0027] like Figure 4 (ad), CuCoNiS x / NF at different scan rates (10-60 mV·s) -1 The area under the CV curves under these conditions is greater than that of CuCoNi(OH). x / NF, after ECSA normalization, also showed the highest intrinsic SOR catalytic activity, demonstrating excellent SOR performance.

[0028] 3. CuCoNiS x Stability analysis of / NF The adsorbed S on the electrode surface was determined using a three-electrode system and UV-Vis spectroscopy in a 1 M NaOH solution containing 1 M Na₂S. 2- Concentration. All electrodes were run in a 1 M NaOH solution containing 1 M Na₂S, with a voltage of 0.4 V (vs. RHE) applied. After 120 s of operation, the electrodes were lifted directly above the electrolyte, then transferred while charged and immersed in 10 mL of pure water. Subsequently, the applied voltage was removed, and the electrodes were agitated in pure water for 1 min to allow the S adsorbed on the catalyst surface to settle. 2-Completely release into pure water. After repeating the above process, detect S in the water using ultraviolet-visible spectroscopy. 2- concentration (S) 2- The characteristic absorption peak is located at a wavelength of 230 nm.

[0029] like Figure 5 a, S 2- Adsorption test results show that CuS x S adsorbed on the surface of / NF electrode 2- The quantity is significantly higher than that of CuCoNiS x / NF electrode. This phenomenon can be explained in two ways: first, CuS x For S 2- It exhibits stronger chalcophilicity, leading to strong adsorption of S²⁻ on the surface, but the transformation kinetics are slow. Once the active sites are occupied, catalysis can no longer continue, and unreacted S²⁻... 2- It is eluted during the oscillation process; secondly, CuCoNiS x / NF vs S 2- The adsorption strength is more moderate, and the adsorbed S²⁻ can be rapidly oxidized into the polysulfide intermediate S. x 2- (x=2-6) and further S8 desorption occurs, resulting in a small amount of S²⁻ remaining on the surface. This result indicates that although CuS x CuCoNiS exhibits a low Tafel slope and charge transfer resistance, but its excessive chalcophile properties make its active sites susceptible to poisoning; therefore, CuCoNiS... x / NF exhibits superior short-term stability and long-term durability.

[0030] like Figure 5 As shown in b, CuCoNiS x / NF electrode at 100 mA·cm -2 During continuous operation at current density, the potential remains stable with minimal fluctuations; while CuS x The / NF electrode exhibited a rapid increase and dramatic fluctuation in potential under the same conditions, indicating rapid deactivation of its active sites. This comparison illustrates the effect of the ternary CuCoNiS... x The catalyst exhibits excellent electrochemical stability, effectively resisting sulfur poisoning and maintaining sustained catalytic activity. At a constant potential, CuS... x The current density of / NF decreases sharply over time. Figure 5 c) indicates that single-metal sulfide catalysts are prone to surface poisoning in sulfur oxidation reactions, with active sites being blocked by intermediate products, leading to a rapid loss of catalytic performance.

[0031] like Figure 5 d, After a long period of constant current operation, CuCoNiS xThe polarization curves of / NF almost overlap, and the current density retention rate is high, indicating that the active sites of this ternary metal sulfide catalyst remain intact during repeated oxidation-reduction processes, and it has good structural stability and resistance to sulfur poisoning.

[0032] 4. CuCoNiS x SOR Product Analysis of / NF To analyze the composition of the anode products, in-situ Raman spectroscopy was used to monitor CuCoNiS in real time. x / NF and CuS x Species evolution on the surface of / NF electrodes. For example... Figure 6 As shown, the results indicate that both catalysts follow the same sulfur oxidation reaction pathway: S 2- It is first adsorbed and activated, and then gradually oxidized to form the polysulfide intermediate S. x 2- (x=2-6), eventually transforming into S8. Specifically, the reaction undergoes "S 2- The complete process of adsorption → oxidation → formation of polysulfides → product S8". For CuCoNiS x The S8 characteristic peak intensity at the / NF electrode is weak and continuously decaying, indicating that the generated S8 is easily desorbed from the catalyst surface, avoiding blockage of active sites and enabling the catalytic reaction to proceed continuously and efficiently without significant material accumulation throughout the process. Figure 6 a). In contrast, CuS x Significant S8 signal accumulation was observed on the / NF electrode surface ( Figure 6 (b) indicates that S8 is over-adsorbed on the surface of monometallic sulfides and is difficult to desorb, which hinders the transformation of intermediate products and poisons the catalytic sites.

[0033] This indicates that the ternary CuCoNiS x The catalyst, through a synergistic effect of multiple metals, significantly improved the adsorption strength of reaction intermediates, enhancing catalytic stability and resistance to sulfur poisoning. Notably, the light yellow electrolyte gradually turned dark yellow due to the formation of polysulfides in the electrolyte.

[0034] 5. CuCoNiS x HER performance analysis of / NF like Figure 7 (a, b), CuCoNiS x CuCoNiS exhibits excellent HER performance. x Only a potential of 0.43 Vvs. RHE is required to reach 100 mA·cm. -2 The current density is lower than that of CuS. x (0.49 Vvs .RHE). For example... Figure 7 c, CuCoNiS xThe Tafel slope is 75.66 mV·dec -1 Lower than CuS x (165.84 mV·dec -1 This indicates that the HER reaction kinetics of the catalyst are faster. (CuCoNiS) x The charge transfer resistance is the smallest ( Figure 7 d) Both the electrocatalytic performance and HER reaction kinetics are superior to CuS. x .

[0035] 6. CuCoNiS x Performance analysis of SOR / / HER dual-function in / NF like Figure 8 As shown, CuCoNiS x It exhibits excellent SOR / / HER bifunctional catalytic properties. For example... Figure 8 a. Compared to the OER / / HER system, the SOR / / HER system achieves a current density of 100 mA·cm⁻¹. -2 and 200 mA·cm -2 The potentials decreased significantly by 1.26 and 1.28 V, and the oxidation potential decreased significantly. The SOR / / HER system only requires a low potential of 0.24 V compared to RHE to reach 100 mA·cm⁻¹. -2 current density ( Figure 8 b), significantly lower than the OER / / HER system (1.50 V vs .RHE). This indicates that replacing OER with SOR significantly reduces the reaction potential, CuCoNiS x The catalyst exhibits excellent electrocatalytic activity for both SOR and HER, enabling the entire electrolysis system to operate at high current density at lower potentials, providing a new strategy for developing efficient and low-energy-consumption water electrolysis for hydrogen production and sulfur oxidation.

Claims

1. Ternary transition metal sulfides (CuCoNiS) x The bifunctional electrocatalytic sulfur oxidation coupled to hydrogen production is characterized by, The method is as follows: An electrolytic cell containing a cation exchange membrane was used, with a ternary transition metal sulfide material supported on a nickel foam substrate as both the cathode and anode. Sodium hydroxide solution was added to the cathode reaction chamber as the cathode electrolyte, and sodium hydroxide and sodium sulfide solutions were added to the anode reaction chamber as the anode electrolyte. The electrolytes in the anode and cathode reaction chambers underwent a coupled electrolytic reaction at room temperature and with stirring. Finally, sulfur was obtained as the product in the anode reaction chamber, and hydrogen was obtained as the product in the cathode reaction chamber. The bifunctional catalyst was prepared by the following method: (1) Cleaning the nickel foam substrate (2) Prepare an electrolyte containing copper nitrate (Cu(NO3)2), nickel nitrate (Ni(NO3)2), and cobalt nitrate (Co(NO3)2). In the electrolyte, the cleaned nickel foam, Ag / AgCl and platinum mesh from step (1) are used as the working electrode, reference electrode and counter electrode, respectively, and treated at the reduction potential for a period of time; After the reaction is complete, the resulting material is washed and dried.

2. (3) Prepare an electrolyte containing sodium sulfide nonahydrate, add the nickel foam obtained in step (2), and keep it in the reactor for a certain period of time; wash and dry the obtained material.

3. The method as described in claim 1, characterized in that, The amount of Cu(NO3)2, Ni(NO3)2, and Co(NO3)2 added was 0.4 mmol each, dissolved in 50 mL of deionized water.

4. The method as described in claim 1, characterized in that, The solution should be stirred for 25–30 minutes.

5. The method as described in claim 1, characterized in that, The reduction potential was -1.0 V vs. Ag / AgCl, and the reaction time was 15 min.

6. The method as described in claim 1, characterized in that, Wash the material with deionized water and dry it at room temperature.

7. The method as described in claim 1, characterized in that, The amount of Na2S·9H2O added was 0.7–0.8 mmol, dissolved in 40 mL of deionized water.

8. The method as described in claim 1, characterized in that, The reaction temperature in the reactor is 110–130℃, and the reaction time is 8 h.

9. The method as described in claim 1, characterized in that, The material was washed three times each with deionized water and anhydrous ethanol, and then vacuum dried at 50–70 °C.

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